Delays to institutionalization were compared between elderly individuals who differed in the amounts ("dosages") of adult day services (ADS) they attended. A Kaplan–Meier survival analysis revealed higher dosages of ADS to be associated with greater delays to institutionalization. Retrospective data from financial and service utilization systems and from the Resident Assessment Instrument for Home Care (RAI-HC) were then used to fit a Cox regression model that was adjusted for potential selection biases. This model also found systematically lower hazards for institutionalization at higher ADS dosages. The ADS effect did not appear to be an artifact of increased utilization of additional home health services. Results suggest a beneficial effect of ADS on delay to institutionalization that cannot be attributed to home support, respite, or case management services.